Bias Adjustment - Yaesu FT-902DM Instruction Manual

ll. KEYER ADJUSTMENT
YR, 02 Controls the Uot-lo-space ratio for the
built-in electronte kever: this is nermally set to
Ii} at the factory. VRaoo, adjusts the symmetry
Once VRyso) 18 set
all keying speeds, Ad
make both
with respect to the
xetween dots. and dashes
s correct for
VRo-
uniformly
this setting
justment of will dots and
o2
change
Both of these
dashe
space controls are located 6n
A:
ve
tab
—
th
n
>.
Kever unit (PB-1728A)
12. CLARIFIER ADJUSTMENT
With the
the RX Cl
FIER
any band und then
button OFF, Lf the
potentiometer VR o,. which is. located
ARTPIER control
mode
the CLARI
Tune in the marker signal on
the RX CLARIFIER
frequency changes at all,
transceiver in the receive
ARIFIER button and set
to Ul.
pusn
control
switel
adjust
imside the cabinet near the Cl
poOtentome ter.
M12
(VEO writ)
Tune board
PB-1720)
VR Band switeh
13. VOLTAGE REGULATOR ADJUSTMENT
Connect a VTVM [x
MJ, (PB-1717A) and
potentiometer VRy xo,
indicated an the VTVM
probe between pin 10 of
Adjust 6V SFI
Volts: as
ground.
exactly 6
PO
l4. BIAS ADJUSTMENT
Phe
hee ked to
final amplifier bias must be ensure
linearity and normal operating plate dissipation
for the final amplifier tubes, Adjust the BIAS
control VRy qq, on PB-17O8A as follows: set the
transceiver in the receive mode and allow th:
lubes to reach normal operating temperatun
Set the MODE switch to USB, the METER switch
to IC. and the VOX GAIN control to MOX, soa
is to activate the transmitter. The meter will
then indicate cathode current for the PA tuhes
The idling cathode current is 50 mA if the bias
is correct (25 mA lor the SD model). If the idling
current js other than S50 mA, acdiust the
BIAS control VR, yo, forthe
cuthode
correct value.
—s
averr
—_
_ & #uURE
A Sz {
= 3
(PB-1708)
Rectiier A unr